<?php

declare(strict_types=1);

namespace Doctrine\ORM\Tools\Pagination;

use Doctrine\ORM\Mapping\AssociationMetadata;
use Doctrine\ORM\Mapping\ToOneAssociationMetadata;
use Doctrine\ORM\Query\AST\ArithmeticExpression;
use Doctrine\ORM\Query\AST\ConditionalExpression;
use Doctrine\ORM\Query\AST\ConditionalFactor;
use Doctrine\ORM\Query\AST\ConditionalPrimary;
use Doctrine\ORM\Query\AST\ConditionalTerm;
use Doctrine\ORM\Query\AST\InExpression;
use Doctrine\ORM\Query\AST\InputParameter;
use Doctrine\ORM\Query\AST\NullComparisonExpression;
use Doctrine\ORM\Query\AST\PathExpression;
use Doctrine\ORM\Query\AST\SelectStatement;
use Doctrine\ORM\Query\AST\SimpleArithmeticExpression;
use Doctrine\ORM\Query\AST\WhereClause;
use Doctrine\ORM\Query\TreeWalkerAdapter;
use function count;
use function reset;

/**
 * Replaces the whereClause of the AST with a WHERE id IN (:foo_1, :foo_2) equivalent.
 */
class WhereInWalker extends TreeWalkerAdapter
{
    /**
     * ID Count hint name.
     */
    public const HINT_PAGINATOR_ID_COUNT = 'doctrine.id.count';

    /**
     * Primary key alias for query.
     */
    public const PAGINATOR_ID_ALIAS = 'dpid';

    /**
     * Replaces the whereClause in the AST.
     *
     * Generates a clause equivalent to WHERE IN (:dpid_1, :dpid_2, ...)
     *
     * The parameter namespace (dpid) is defined by
     * the PAGINATOR_ID_ALIAS
     *
     * The total number of parameters is retrieved from
     * the HINT_PAGINATOR_ID_COUNT query hint.
     *
     * @throws \RuntimeException
     */
    public function walkSelectStatement(SelectStatement $AST)
    {
        $queryComponents = $this->getQueryComponents();
        // Get the root entity and alias from the AST fromClause
        $from = $AST->fromClause->identificationVariableDeclarations;

        if (count($from) > 1) {
            throw new \RuntimeException('Cannot count query which selects two FROM components, cannot make distinction');
        }

        $fromRoot  = reset($from);
        $rootAlias = $fromRoot->rangeVariableDeclaration->aliasIdentificationVariable;
        $rootClass = $queryComponents[$rootAlias]['metadata'];
        $property  = $rootClass->getProperty($rootClass->getSingleIdentifierFieldName());
        $pathType  = PathExpression::TYPE_STATE_FIELD;

        if ($property instanceof AssociationMetadata) {
            $pathType = $property instanceof ToOneAssociationMetadata
                ? PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION
                : PathExpression::TYPE_COLLECTION_VALUED_ASSOCIATION
            ;
        }

        $pathExpression = new PathExpression(
            PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION,
            $rootAlias,
            $property->getName()
        );

        $pathExpression->type = $pathType;

        $count = $this->getQuery()->getHint(self::HINT_PAGINATOR_ID_COUNT);

        if ($count > 0) {
            $arithmeticExpression                             = new ArithmeticExpression();
            $arithmeticExpression->simpleArithmeticExpression = new SimpleArithmeticExpression(
                [$pathExpression]
            );
            $expression                                       = new InExpression($arithmeticExpression);
            $expression->literals[]                           = new InputParameter(':' . self::PAGINATOR_ID_ALIAS);
        } else {
            $expression      = new NullComparisonExpression($pathExpression);
            $expression->not = false;
        }

        $conditionalPrimary                              = new ConditionalPrimary();
        $conditionalPrimary->simpleConditionalExpression = $expression;

        if ($AST->whereClause) {
            if ($AST->whereClause->conditionalExpression instanceof ConditionalTerm) {
                $AST->whereClause->conditionalExpression->conditionalFactors[] = $conditionalPrimary;
            } elseif ($AST->whereClause->conditionalExpression instanceof ConditionalPrimary) {
                $AST->whereClause->conditionalExpression = new ConditionalExpression(
                    [new ConditionalTerm(
                        [
                                $AST->whereClause->conditionalExpression,
                                $conditionalPrimary,
                            ]
                    ),
                    ]
                );
            } elseif ($AST->whereClause->conditionalExpression instanceof ConditionalExpression
                || $AST->whereClause->conditionalExpression instanceof ConditionalFactor
            ) {
                $tmpPrimary                              = new ConditionalPrimary();
                $tmpPrimary->conditionalExpression       = $AST->whereClause->conditionalExpression;
                $AST->whereClause->conditionalExpression = new ConditionalTerm(
                    [
                        $tmpPrimary,
                        $conditionalPrimary,
                    ]
                );
            }
        } else {
            $AST->whereClause = new WhereClause(
                new ConditionalExpression(
                    [new ConditionalTerm([$conditionalPrimary])]
                )
            );
        }
    }
}
